Optical on/off switches are used in optical systems for various functions, such as add/drop multiplexers and amplitude modulators. A primary use of on/off switches is to modulate amplitude of continuous wave signals. Additionally, an on/off switch can block of a signal at some location when a broadcast signal is not meant to be received at that location.
Switches often incorporate mirrors or other movable blocking mechanisms. The signal is blocked when a mirror or beam is moved into the path of an optical beam propagating from one waveguide to another. When the mirror is moved out of the path of an optical beam, the beam is coupled to the second waveguide. Moving parts may become stuck in an on or off position so that the signal is permanently blocked or coupled. Material fatigue after extended use also causes failure of moving parts used in on/off switches. The properties of a material forming a micro-electromechanical system (MEMS) hinge, for example, may change after hundreds of rotations, degrading the range of motion available from the hinge.
It would be desirable to have an optical switch that would overcome the above disadvantages.